diff --git a/core/phpcs.xml.dist b/core/phpcs.xml.dist
index ed5acf2e732dfeb6f57a9534457f0a52049e2ede..015d8633e3bb59942f881dd76e1d26506f7afc48 100644
--- a/core/phpcs.xml.dist
+++ b/core/phpcs.xml.dist
@@ -268,6 +268,12 @@
        </property>
     </properties>
   </rule>
+  <rule ref="SlevomatCodingStandard.TypeHints.DeclareStrictTypes">
+    <properties>
+      <property name="spacesCountAroundEqualsSign" value="0" />
+    </properties>
+    <include-pattern>./tests/Drupal/BuildTests/*</include-pattern>
+  </rule>
 
   <!-- Squiz sniffs -->
   <rule ref="Squiz.Arrays.ArrayBracketSpacing"/>
diff --git a/core/tests/Drupal/BuildTests/Composer/Component/ComponentsIsolatedBuildTest.php b/core/tests/Drupal/BuildTests/Composer/Component/ComponentsIsolatedBuildTest.php
index fe72a958a6b25c310d379e6ce592ee5a9fefe375..9891f10897ca596176d311233b7a015bfcd24b7b 100644
--- a/core/tests/Drupal/BuildTests/Composer/Component/ComponentsIsolatedBuildTest.php
+++ b/core/tests/Drupal/BuildTests/Composer/Component/ComponentsIsolatedBuildTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Composer\Component;
 
 use Drupal\BuildTests\Composer\ComposerBuildTestBase;
diff --git a/core/tests/Drupal/BuildTests/Composer/Component/ComponentsTaggedReleaseTest.php b/core/tests/Drupal/BuildTests/Composer/Component/ComponentsTaggedReleaseTest.php
index df12ea6b763cd9225790939d4d23515c50844c3b..ae3a08ec3627ec3f7214f35020712b616a6b8f46 100644
--- a/core/tests/Drupal/BuildTests/Composer/Component/ComponentsTaggedReleaseTest.php
+++ b/core/tests/Drupal/BuildTests/Composer/Component/ComponentsTaggedReleaseTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Composer\Component;
 
 use Drupal\BuildTests\Composer\ComposerBuildTestBase;
diff --git a/core/tests/Drupal/BuildTests/Composer/ComposerBuildTestBase.php b/core/tests/Drupal/BuildTests/Composer/ComposerBuildTestBase.php
index 619fd8d10484eb88abae65ee6d6ddb5e828158a3..10f36d62fa0977b478112e3909e21f89ef1c886c 100644
--- a/core/tests/Drupal/BuildTests/Composer/ComposerBuildTestBase.php
+++ b/core/tests/Drupal/BuildTests/Composer/ComposerBuildTestBase.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Composer;
 
 use Drupal\BuildTests\Framework\BuildTestBase;
diff --git a/core/tests/Drupal/BuildTests/Composer/ComposerValidateTest.php b/core/tests/Drupal/BuildTests/Composer/ComposerValidateTest.php
index 13d726056410e6f9eba22e449c59723369575fa6..f510a474d202860d5efbf9d895bf642e3ca288fd 100644
--- a/core/tests/Drupal/BuildTests/Composer/ComposerValidateTest.php
+++ b/core/tests/Drupal/BuildTests/Composer/ComposerValidateTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Composer;
 
 use Drupal\BuildTests\Framework\BuildTestBase;
diff --git a/core/tests/Drupal/BuildTests/Composer/Template/ComposerProjectTemplatesTest.php b/core/tests/Drupal/BuildTests/Composer/Template/ComposerProjectTemplatesTest.php
index 9fd3d4f000b9567abfa5744b7b54101c3a29b082..23d0dbbf68e698e07d161f0d3438a491a8aa042c 100644
--- a/core/tests/Drupal/BuildTests/Composer/Template/ComposerProjectTemplatesTest.php
+++ b/core/tests/Drupal/BuildTests/Composer/Template/ComposerProjectTemplatesTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Composer\Template;
 
 use Composer\Json\JsonFile;
diff --git a/core/tests/Drupal/BuildTests/Framework/BuildTestBase.php b/core/tests/Drupal/BuildTests/Framework/BuildTestBase.php
index ded5b3104128c29b349b36d13847162a056a7279..f566064807d5acc625abeaffe92042c374982354 100644
--- a/core/tests/Drupal/BuildTests/Framework/BuildTestBase.php
+++ b/core/tests/Drupal/BuildTests/Framework/BuildTestBase.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Framework;
 
 use Behat\Mink\Driver\BrowserKitDriver;
diff --git a/core/tests/Drupal/BuildTests/Framework/ExternalCommandRequirementsTrait.php b/core/tests/Drupal/BuildTests/Framework/ExternalCommandRequirementsTrait.php
index a3eb94ea49a615f64a200c8a09637e44bb894db9..68635e21676e22a146cf4a71bb5598f8142d3d25 100644
--- a/core/tests/Drupal/BuildTests/Framework/ExternalCommandRequirementsTrait.php
+++ b/core/tests/Drupal/BuildTests/Framework/ExternalCommandRequirementsTrait.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Framework;
 
 use PHPUnit\Framework\SkippedTestError;
diff --git a/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php b/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php
index 5eeca68e12ea9a55995b461d086f7f6c7b03d666..d58fdacc5fb79f274b447cf72956d4d51d3c8eb5 100644
--- a/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php
+++ b/core/tests/Drupal/BuildTests/Framework/Tests/BuildTestTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Framework\Tests;
 
 use Drupal\BuildTests\Framework\BuildTestBase;
diff --git a/core/tests/Drupal/BuildTests/Framework/Tests/ExternalCommandRequirementTest.php b/core/tests/Drupal/BuildTests/Framework/Tests/ExternalCommandRequirementTest.php
index ccbbd7261a8471d4ac9680b575dffd40390b5e10..8d260cb827e1d66258ae4c6062b610ec85280299 100644
--- a/core/tests/Drupal/BuildTests/Framework/Tests/ExternalCommandRequirementTest.php
+++ b/core/tests/Drupal/BuildTests/Framework/Tests/ExternalCommandRequirementTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Framework\Tests;
 
 use Drupal\BuildTests\Framework\ExternalCommandRequirementsTrait;
diff --git a/core/tests/Drupal/BuildTests/Framework/Tests/HtRouterTest.php b/core/tests/Drupal/BuildTests/Framework/Tests/HtRouterTest.php
index 9e90a19270e07f78cdce0db995545ed6e1832f19..19c439c876d5739068b0cbe6ce37f32e7efb00a5 100644
--- a/core/tests/Drupal/BuildTests/Framework/Tests/HtRouterTest.php
+++ b/core/tests/Drupal/BuildTests/Framework/Tests/HtRouterTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\Framework\Tests;
 
 use Drupal\BuildTests\QuickStart\QuickStartTestBase;
diff --git a/core/tests/Drupal/BuildTests/QuickStart/QuickStartTestBase.php b/core/tests/Drupal/BuildTests/QuickStart/QuickStartTestBase.php
index 3424c228132f6c7088bc49d320194f0fa41e3115..1ee4602e636aff4756fb09112cb293067c225af8 100644
--- a/core/tests/Drupal/BuildTests/QuickStart/QuickStartTestBase.php
+++ b/core/tests/Drupal/BuildTests/QuickStart/QuickStartTestBase.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\QuickStart;
 
 use Drupal\BuildTests\Framework\BuildTestBase;
diff --git a/core/tests/Drupal/BuildTests/TestSiteApplication/InstallTest.php b/core/tests/Drupal/BuildTests/TestSiteApplication/InstallTest.php
index cc431a9aa8555a3569384e84696a1a420098e3b4..a97099ecb1d1dd987612e10e2f81dc0a924754e5 100644
--- a/core/tests/Drupal/BuildTests/TestSiteApplication/InstallTest.php
+++ b/core/tests/Drupal/BuildTests/TestSiteApplication/InstallTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\BuildTests\TestSiteApplication;
 
 use Drupal\BuildTests\Framework\BuildTestBase;